1. Field of the Invention
The present invention is directed to an airborne weather and ground mapping radar system which improves location accuracy of weather and ground features and more particularly to a system that provides at least a two segment approximation for rain attenuation and uses a sliding azimuth window to produce an improved signal to noise ratio.
2. Description of the Related Art
Conventional weather radar determines the location and magnitude of weather features from the reflection of the radar signal from precipitation. Radar signals attenuate as they pass through precipitation and, as result, a return from a range cell deep in a precipitation region is attenuated more than a return from a range cell not as deep in the precipitation region, thereby causing returns received by the radar system to in- accurately portray the weather features. In addition as rain rates change from low to high the attenuation increases, further increasing the inaccuracy of the weather features shown by the radar display. Conventional radar system such as described in U.S. Pat. Nos. 4,835,536, 4,223,309 and RE 33,152 do not take into account the increased attenuation caused by higher rain rates and only provide a linear compensation for a single low rain rate. As a result, pilots using conventional weather radar systems do not receive an accurate picture of the weather deep in or behind precipitation regions. What is needed is a system that accurately depicts the weather throughout a weather system.